1. Field of the Invention
The present invention relates to a shielded electrical connector, and particularly to a shielded USB (Universal Serial Bus) connector having spring fingers provided on a shield thereof for ensuring a reliable engagement between the USB connector and a complementary plug connector.
2. Description of Prior Art
USB connectors are increasingly used in the electrical connector field and are intended to integrate most different types of I/O connectors, such as D-Sub connectors and Mini-Dins, into a standard form. A shield is often used to enclose the USB connector housing for protection against electromagnetic interference. To ensure a reliable engagement between the USB connector and a complementary plug connector, a plurality of spring fingers are integrally stamped from peripheral surfaces of the shield of the USB connector for engaging with the complementary plug connector, thereby retaining the complementary plug connector in a mated position. Such a design is disclosed in U.S. Pat. Nos. 5,738,544; 5,779,489 and 5,928,035. The disadvantage of this design is that repeated stamping processes are required, thereby complicating manufacturing. In addition, the shielding performance is also degraded.
Another relatively simple approach for retaining a complementary plug connector in position is to provide a pair of opposite, rearwardly extending spring fingers at opposite lateral edges of a rectangular opening of a shield adapted to receive the complementary plug connector. Relevant designs are disclosed in U.S. Pat. Nos. 5,083,945; 5,207,597 and 5,378,172. However, since the pair of spring fingers is stamped from the shield and is typically arranged symmetrically, the sum of the lengths of the spring fingers is limited to the length of a longitudinal edge by the rectangular opening. Accordingly, the retention force of the spring fingers may be insufficient to reliably retain the complementary plug connector in position.
Therefore, it is desirable to have a shield with a pair of spring fingers each having sufficient length to reliably retain a complementary plug connector in position.